Rust FFI and C Memory Ownership Transfer

Integrating Rust with C via the Foreign Function Interface (FFI) requires a strict protocol for managing heap-allocated memory across the language boundary. When Rust transfers ownership of a resource to a C consumer using Box::into_raw, the Rust compiler ceases to track the lifetime of that allocation.

The primary constraint is ensuring that the memory is reclaimed without causing undefined behavior. Since C lacks a native understanding of Rust's ownership model, the responsibility for triggering the destructor falls on the integration layer, typically requiring the pointer to be passed back to a specific Rust function for reconstruction via Box::from_raw.

• How can the integration be structured to guarantee that Box::from_raw is called exactly once for every Box::into_raw call?
• What is the recommended pattern for verifying that the pointer passed back from C still matches the original allocation layout expected by the Rust allocator?